Cast iron ductile pipe is used as a gate valve, and the connection method of ductile iron pipe

Here are some of the well-known brands recognized in the valve industry, which are widely recognized and have a high reputation. While rankings may vary depending on time and market conditions, the following brands are generally considered to be among the top brands in the valve industry:

The following influential first-line brands of water system valves and industrial valves can be used as a reference, but for reference only: Suzhou Neway Valve, Shanghai Guanlong Valve, Shanghai Qizhong Valve, Sanhua, Su Yan, Shentong, Su Valve, Nanfang, Jiang.

First, the word Yao. The above manufacturers are only estimates and references, and the specific situation may vary or fluctuate at any time due to changes in a series of factors such as changes in the market, the size of the competition pattern, and the stability of product quality. As an indispensable key device in industrial production and civil facilities, the quality and reputation of the valve brand directly affect the satisfaction and trust of users.

These brands are known in the valve industry for their innovative technology, high-quality products and reliability. It is important to note that the market and industry are evolving rapidly, and different rankings may vary depending on time and region. For the most up-to-date ranking information, it is recommended to refer to industry reports, professional organizations or market research data for more detailed and accurate information.

1. Flange connection: This method is a general connection method, and the principle of this method is that the ductile iron pipe and steel pipe are converted into flange interfaces, so as to achieve standard docking. There are two kinds of standard pipe fittings for ductile iron pipes, namely disc bearing short pipes and coil plug short pipes, and the sockets or sockets of the pipe fittings can be connected to the normal pipeline, so that the pipeline can be converted into a flange interface, and only need to be connected with the corresponding steel flange.

The characteristics of this method are: the connection method is more general, and the flange is made as a standard part to ensure the stability of the connection. When purchasing and installing, it should be noted that the flanges of both sides not only need to have the same nominal value, but also the pn value should be consistent in order to be connected.

Only if the PN value is consistent, the number of holes and hole spacing of the flange can be consistent, otherwise it cannot be installed, and will cause returns and construction delays.

2. Socket connection: The method of socket connection is to ensure that the connection position is the socket for the ductile iron pipe (if not, use a double socket sleeve to make the socket end convert to the socket end), and the steel pipe end is welded with an additional layer of steel plate in its outer diameter of the socket, so that the outer diameter of the steel pipe is guaranteed to be the same as the outer diameter of the ductile iron pipe. The steel pipe is then inserted into the socket of the ductile iron pipe for installation.

The advantage of socket connections is that there is no risk of corrosion from bolt burial. However, for large-diameter pipelines, the wall thickness of the steel pipe is thin, and the steel pipe is protruding from the well chamber, the radial deformation of the steel pipe may be too large due to the settlement of the well chamber, so that there is a risk of interface leakage.

There are usually three connection methods for ductile iron pipes, namely: rigid waterproof wing ring installation and lifting mode, rigid waterproof casing installation method, and K-type interface flexible installation method.

1. Rigid waterproof wing ring installation method

The water-stop ring is welded on the ductile iron pipe, and when the reinforced concrete wall is constructed, it is directly poured into it in one piece.

This method uses the most economical materials, but the welding of ductile iron pipes requires a special welding process, so it must be welded in the factory, and cannot be routinely welded on site.

In addition, ductile iron pipes are conventionally T-shaped socket connections, so if the rigid waterproof wing ring installation method is adopted, the pipeline must be installed first, and then according to the old position of the pipeline, the inspection well must be poured last.

If the inspection wells at both ends are done first, and then the pipeline is installed, the last section will not be able to be plugged in.

2. Rigid waterproof casing installation method

A cast iron casing (with a waterstop ring) is set outside the ductile iron pipe, and the cast iron casing is supplied to the finished product of the factory (made by pouring molten iron directly by using a mold).

When the cast iron casing is constructed on the reinforced concrete wall, it is directly poured into it as a whole.

Then install the pipeline, and finally use the caulking sealing material for the gap between the pipe and the casing, and the commonly used sealing material is the middle oil hemp winding, and the asbestos cement caulking at both ends.

This kind of installation method requires the fine coordination of the length of pipeline cutting and the setting of the inspection well position, otherwise it is easy to appear that the stove Zheng pipeline in the well is too long and needs to be cut.

In addition, this is a rigid connection method, and the anti-settling performance at the interface is very poor.

3. K-type interface flexible installation mode

A K-type wall flange sleeve (with a water-stop foil ring) is set outside the ductile iron pipe, and the K-type wall flange sleeve is supplied to the factory finished product (made by directly pouring molten iron by using a mold).

The K-type wall flange casing is directly poured into it in one piece during the construction of the reinforced concrete wall.

Then install the pipe, and finally fill the gap between the pipe and the casing with a rubber sealing ring, and press it with a flange gland and fix it with bolts.

Cast Iron Pipe Features:

In terms of quality, the spheroidization grade of cast iron pipe is controlled to be 1-3 (nodularity rate of 80%), so the mechanical properties of the material itself have been well improved, with the essence of iron and the properties of steel.

After annealing, the metallographic structure of the annealed ductile iron pipe is ferrite plus a small amount of pearlite, which has good mechanical properties, excellent anti-corrosion performance, good ductility performance, good sealing effect and easy installation.

It is mainly used for water supply, gas transportation, oil transportation and so on in municipal, industrial and mining enterprises.

Connection method of ductile iron pipe:

The ordinary socket connection is divided into flexible connection that is T type, mechanical connection is K type, flange connection PN10 PN16 PN25.

Ductile iron pipe groove connection fittings include two categories of products:

1. The pipe fittings that play the role of connection and sealing include rigid joints, flexible joints, mechanical tees and grooved flanges;

2. The pipe fittings that play the role of connection transition include elbow, tee, cross, reducer, blind plate, etc.

The groove connection pipe fittings that play the role of connection sealing are mainly composed of:

Seals rubber rings, clamps and locking bolts. The rubber seal on the inner layer is placed on the outside of the connected pipe and coincides with the pre-rolled groove, and the ductile iron pipe is then fastened with a clamp on the outside of the rubber ring and then fastened with two bolts. Due to the unique sealable structure design of its rubber sealing ring and clamp, the groove connection has good sealing, and its sealing performance is correspondingly enhanced with the increase of fluid pressure in the pipe.

The ordinary socket connection is divided into flexible connection that is T type, mechanical connection is K type, flange connection PN10 PN16 PN25.

Flange connection is adopted.

The connection method of ductile iron pipe is flange connection, and for the flange connection method, it cannot be directly buried, which will cause problems such as water leakage at the connection port.

Superiority of ductile iron pipes:

Because the ductile iron pipe fittings adopt flexible joints, the construction operation is more convenient, which can improve the construction efficiency, improve the construction conditions, reduce the construction cost, and most of the interfaces are connected with rubber rings, which is easy to operate, can shorten the construction period and reduce the construction cost.

Ductile iron pipe fittings have the advantages of high water supply pressure, resistance to external load and adaptation to changes in geological conditions, and pipe has the advantages of high strength, good toughness, corrosion resistance, slow and convenient installation of flexible interfaces, strong seismic resistance and low labor intensity.

It can be applied to the poor geological section and the crossing road, without the need for additional processing of steel pipes, coupled with strong corrosion resistance, it can be applied to coastal and saline-alkali areas. It is widely used in underground pipeline engineering. Large-scale pipeline installation projects can better reflect its advantages of convenient installation and low labor intensity.

Ductile iron pipe fittings have good sealing performance and are not easy to leak, which can reduce the leakage rate of the pipe network and reduce the daily maintenance cost of the pipe network. Magnesium or rare earth magnesium combined with gold nodularizing agent is added to the molten iron before pouring, so that the graphite is spheroidized, the stress concentration is reduced, and the pipe has the advantages of high strength, high elongation, impact resistance, corrosion resistance, and good sealing. <>